Summary A privately owned Cessna182 (C-FTGQ, registration18253153) was on a day visual flight rules flight from Victoria, British Columbia, to Vancouver International Airport, British Columbia. The aircraft's skin was unpainted aluminum. When the Cessna was about five nautical miles from the airport, the Vancouver Tower south (TS) controller cleared the pilot to proceed directly to the threshold of Runway08 right (08R), the active runway. At the same time, a WestJet Airlines Boeing737 (WJA168) was taxiing to Runway 08R for departure to Calgary, Alberta. Just after the Cessna crossed the threshold, the TS controller cleared WJA168, then holding at the threshold, to take position on Runway 08R. When the TS controller saw that the Cessna had touched down, he instructed the pilot to exit the runway to the right at Runway12, which was 4500feet from the threshold of Runway 08R, and to contact Vancouver ground control. The pilot correctly read back this instruction. Seconds later, when the TS controller assessed that the Cessna was turning off onto Runway12, he cleared WJA168 for take-off. However, the Cessna pilot had passed the exit to Runway12 and remained on Runway 08R. At about 1437 Pacific standard time, with WJA168 now on its take-off roll, the TS controller was advised that the Cessna was still on the active runway. He immediately instructed the Cessna pilot to vacate the runway quickly at the next taxiway and to stay to the right-hand side of the runway. WJA168 passed abeam of the Cessna, about 200feet above and 100feet to the left, while the Cessna was still on the runway at the entrance toTaxiwayA2. Ce rapport est galement disponible en franais. Other Factual Information The following control positions in the tower were staffed: Vancouver tower south (TS), ground south (GS), tower advisory (TA), and combined tower/ground north positions. At the time of the incident, the traffic level for the TS controller was light to moderate and included a few arrivals interspersed with a steady stream of departures. The TS controller was responsible for arrivals and departures on runways08Rand12. The weather at 1420 Pacific standard time1 was reported as follows: wind 130True at 5knots, visibility 10statute miles, light rain showers, a few clouds at 1200feet, ceiling 1900 feet broken, 5000feet overcast, altimeter setting29.96, remarks: ceiling ragged. The weather at 1439 was as follows: wind 140True at 6knots, visibility 8miles, ceiling 1600feet broken, 2500feet overcast, altimeter setting29.96. There was no indication that the runway was wet at the time of the incident, although it was reported that there were puddles of water in the infield grass. When over Active Pass at 1300feet above mean sea level (asl), approximately 20nautical miles (nm) south of Vancouver International Airport, the Cessna pilot contacted the TA controller at 1424:41. The TA controller cleared the Cessna for a Sandheads visual flight rules arrival procedure for Runway 08R and issued the current altimeter setting. At 1432:45, the TAcontroller instructed the Cessna pilot to follow a ShortsSD-360 aircraft that was two miles ahead and to contact the Vancouver tower south (TS) controller. The pilot advised that the traffic was in sight. The Cessna pilot contacted the TS controller at 1432:57 and was advised that he was number two on approach behind the ShortsSD-360, which was then three miles ahead. The TS controller had just requested that the ShortsSD-360 fly directly to the threshold of Runway08R and keep the speed up. The TS controller asked the Cessna to keep the base leg for Runway08R square to keep the traffic pattern close to the airport to reduce the possibility of delays to departing traffic. At the time, there were three aircraft waiting for departure. Twenty seconds later, the controller again requested that the Cessna keep the base leg square, and advised that jet traffic would be departing ahead and that the Cessna was now number one in the landing sequence. At 1435:14, the TS controller instructed C-FTGQ to fly directly to the threshold ofRunway08R. At 1435:53, the TS controller cleared the Cessna to land on Runway08R. The Cessna crossed the threshold at a ground speed of 85to 90knots, approximately 30knots faster than usual for this aircraft.2 Once the Cessna had passed the threshold of Runway08R, the TS controller cleared WJA168, which was the next aircraft in line for departure, to take position on Runway 08R. At 1437:37, the TS controller instructed the Cessna to exit Runway08R onto Runway12 and to contact the ground controller on frequency 121.7MHz. The pilot acknowledged the instruction. The TS controller had earlier issued similar exit instructions to a Beech1900 landing on Runway08R, and that aircraft had exited onto Runway12 without difficulty. When the TS controller issued exit instructions to the Cessna, he believed that the aircraft had already touched down; however, it was still airborne in the landing flare. The pilot had flown down the runway for a considerable distance to lose the extra speed, and the aircraft did not touch down until it was a few hundred feet short of the intersection with Runway12. As soon as the Cessna touched down, the pilot applied the wheel brakes; however, the aircraft was light on its wheels and started to skid to the right. The pilot immediately released the brakes and applied power to maintain directional control. The aircraft was travelling too fast to turn onto Runway12 or onto the next available taxiway,E/H. The pilot, who was relatively unfamiliar with Vancouver International Airport, was now unsure of his position with respect to Runway12, but was hesitant to ask for further taxi directions. The pilot did not advise the TS controller that he had not turned off the runway as instructed (seeAppendixA) nor did he ask for further taxi directions. The pilot assumed that it would be quite apparent to the controller that he had not turned ontoRunway12. After having issued exit instructions to the Cessna, the TS controller, in accordance with established procedures, handed the flight data strip for the aircraft to the GS controller. He then looked up and observed what he thought was the Cessna commencing a turn to exit Runway08R onto Runway12. The TS controller then issued the take-off clearance to WJA168. He did not confirm that the Cessna was off the runway, nor did he see the Cessna on the runway during a subsequent scan of Runway 08R. The Cessna pilot did not hear the TS controller issue the take-off clearance to WJA168 even if he was monitoring the same frequency. WJA168 was on TaxiwayL at the threshold of Runway 08R when the Cessna crossed the landing threshold. On receiving clearance to taxi into position, the crew of WJA168 scanned the runway approach and departure paths and taxied onto the runway. While WJA168 was lining up with the runway centreline, it was cleared for take-off. The pilot flying again scanned the runway, and the pilot not flying completed the remaining items on the pre-take-off checklist. Neither pilot noted that the Cessna was still on the runway. After WJA168 had passed 80knots on the take-off run, the pilot flying saw a light ahead near the side of the runway. He alerted the pilot not flying, and both pilots looked for the source of the light. On hearing the TS controller instruct an aircraft to expeditiously vacate the runway, the pilot flying saw the Cessna. Assessing the situation, he determined that there was sufficient room to continue the take-off and avoid the other aircraft, rather than abort the take-off at high speed thus risking a collision on the runway. WJA168 rotated at approximately 145knots just beyond the intersection of Runway12. A replay of the airport surface detection equipment (ASDE) radar showed that WJA168 passed approximately 100feet to the left of the Cessna at an estimated height of approximately 200feet. At the time, the Cessna was still on the runway at the entrance toTaxiwayA2. The GS controller, who was expecting the Cessna to contact him once clear of the runway, spotted the Cessna still on the runway while WJA168 was in the take-off roll. He immediately alerted the TS controller and then, on the south ground frequency, instructed the Cessna to get off the runway, adding that a jet was taking off from behind. The Cessna pilot did not receive these instructions because he was still monitoring the south tower frequency. When informed that the Cessna was still on the runway, the TS controller made a visual assessment of the situation, including the speeds and positions of both aircraft, and decided not to instruct WJA168 to abort the take-off. He then instructed the Cessna to immediately get off the runway at the next exit, repeating the word expedite several times. After the TS controller cleared WJA168 for take-off, he entered a departure time on the paper flight data strip and then moved the electronic flight data strip on the extended computer display system (EXCDS)3 to the departure section of the screen. The flight data strip for WJA168 then appeared on the departure controller's screen, negating the requirement for verbal communication with the departure controller to indicate that WJA168 had departed. The TS controller then cleared the next aircraft in line to take position on Runway08R, which required him to slide the paper strip for that aircraft part way out of the holder to indicate that the aircraft was on the runway. These activities required the TS controller to focus his attention inside the tower and reduced the time available for him to look out onto the airfield. Human vision is subject to numerous inherent limitations that affect the ability of an individual to discern and visually acquire an object. A number of studies have been conducted to determine how pilots search and scan for conflicting aircraft in the air and to explore why aircraft are frequently not detected visually. Some of the results of these studies are applicable to air traffic controllers scanning a runway or taxiway to determine if there are any obstructions that could affect the safety of aircraft manoeuvring on the ground. For example, it has been shown that, when an individual scans rapidly across an area, the movement of the eyes is not smooth, rather the eyes ... shift in a series of jerky movements or jumps called saccades.... A study conducted at the U.S. Naval Aerospace Medical Laboratory showed that when the eyes are in saccadic movement, visual acuity decreases sharply, leaving gaps in the distant field of vision.4 This physiological characteristic greatly reduces the efficiency of visual scanning, often preventing objects from being detected. The NAV CANADA Air Traffic Control Manual of Operations (ATC MANOPS), Part3, Section308, Visual Scanning - Manoeuvring Area, states that controllers have a responsibility ... to visually scan the manoeuvring area thoroughly before issuing clearances or instructions to airport traffic, and, to the extent possible, at other frequent intervals, and to ensure that the runway to be used by a departing or arriving aircraft is free, or will be free, of all known obstacles including vehicles, equipment and personnel before the departing aircraft commences its take-off roll. In addition, a number of scanning techniques and helps are listed in the note to section308.1 of the same publication as follows: scanning has to be systematic; people can get object hypnosis and only see things that move (scanning at least twice will help overcome this); the eyes should move from one point to another (not in one continuous sweep); scanning should be from left to right, the same as you read; and the eye can only focus on an area that would be covered by the fist when your arm is extended in front of you. Recent refresher training for controllers has not included effective visual scanning of manoeuvring surfaces to ensure that there are no hazards or potential conflicts present, nor has it included information on the limits to human vision. ATC MANOPS, Part3, Section352, Arrivals and Departures, prescribes in part that a controller must ensure that a departing aircraft does not begin take-off roll until ... the preceding aircraft has landed and taxied off the runway, or there is every assurance that it will vacate the runway by the time the departure starts the take-off roll. The Aeronautical Information Publication (AIP),5 Rules of the Air (RAC), section4.4.4, indicates that an aircraft is not considered clear of the runway until all parts of the aircraft are past the taxi holding position line or the 200-footpoint. Canadian Aviation Regulations (CARs), Section602.31, specify that a pilot shall comply with and acknowledge, to the appropriate air traffic control unit, all of the air traffic control instructions directed to and received by the pilot-in-command. However, there is no provision that requires a pilot to advise air traffic control immediately when it is not possible to comply with the instruction. The format that air traffic controllers use to issue runway exit instructions is specified in ATC MANOPS, Section345, and includes identification of the aircraft and unit, and specific instructions about the exit and the point at which to contact ground control. A note in the same section states that Unless otherwise instructed by the tower, a landing aircraft will continue to taxi in the landing direction, proceed to the nearest suitable taxiway and exit the runway without delay. There is similar information included in the AIP, section RAC4.4.4. With the exception of exiting a runway onto another runway, pilots should exit on the nearest suitable taxiway and not delay getting off the runway. Specifying a particular exit is at the discretion of the controller; however, the pilot is normally in the best position to determine which exit is most suitable, depending on aircraft speed and runway surface conditions. The ASDE radar at Vancouver International Airport was operating at the time of the incident. This high-definition radar system incorporates a runway incursion monitoring and conflict alert sub-system (RIMCAS) software program. When activated, it provides an alert comprising both an audible and a visual presentation if the system detects a potentially hazardous situation. For example, if a departing aircraft is accelerating for take-off while there is another aircraft, vehicle, or other tracked object on the runway, it generates an alert. At the time of the incident, the RIMCAS program had not yet been activated because of a continuing problem with false targets that caused the ASDE to generate false conflict alerts.